AA 3977 then UA 5191 at O'Hare
Detroit → Chicago → Lancaster
Timetable, Chicago time
14:05AA 3977 from Detroit at the gate
08:50UA 5191 to Lancaster leaves the gate
18 h 45 apart on the timetable, overnight
UA 5191 leaves 18 h 45 after AA 3977 arrives on the timetable: more than half a day, so not a connection we count.